One example of a document printing system is a postage metering system. As is well known, a postage meter is basically an accounting device that securely stores and keeps track of an amount of postage available for printing. Typically, the postage meter includes an ascending register that stores a running total of all postage dispensed by the meter, and a descending register, that holds the remaining amount of postage credited to the meter and that is reduced by the amount of postage dispensed during a transaction. The postage meter generally also includes a control sum register that provides a check upon the descending and ascending registers. The control sum register has a running account of the total amount of funds that have been added into the meter. The control sum register must always correspond with the summed readings of the ascending and descending registers. Thus, the control sum register is the total amount of postage ever put into the machine and it is alterable only when adding funds to the meter. In this manner, by inspecting the various registers and securing them from tampering, the dispensing of postal funds may be accurately recorded, tracked and accounted for.
Traditionally, the postage meter and the printer have been incorporated into a single secure housing. However, recent initiatives by the United States Postal Service (USPS) have enabled the decoupling of the postage meter and the printer. The Information-Based Indicia Program (IBIP) is a distributed trusted system established by the USPS to retrofit and augment existing postage meters using new technology known as information-based indicia. The IBIP relies on digital signature techniques to produce for each mail piece an indicium whose origin cannot be repudiated. Thus, in contrast to traditional postage metering systems employing mechanical printing technology and physical security, the IBIP supports new methods of securely applying postage to mail pieces. Generally, the IBIP requires printing a high density two-dimensional (2D) bar code on a mail piece. The 2D barcode encodes various information associated with the mail piece and is subsequently signed with a digital signature.
The USPS has published detailed specifications for the IBIP. Generally, the IBIP is directed to two types of postage metering systems. The first type is referred to as a closed system and is defined in the INFORMATION BASED INDICIA PROGRAM—PERFORMANCE CRITERIA FOR INFORMATION-BASED INDICIA AND SECURITY ARCHITECTURE FOR CLOSED IBI POSTAGE METERINGS SYSTEMS, dated Jan. 12, 1999, (“IBIP Closed System Specification”). The second type is referred to as an open system and is defined in the INFORMATION BASED INDICIA PROGRAM—PERFORMANCE CRITERIA FOR INFORMATION-BASED INDICIA AND SECURITY ARCHITECTURE FOR OPEN IBI POSTAGE EVIDENCING SYSTEMS, dated Feb. 23, 2000, (“IBIP Open System Specification”). Together, the IBIP Closed System Specification and the IBIP Open System Specification define the requirements for next generation postage metering systems.
Although the open and closed postage metering systems both work generally well, they suffer from certain drawbacks and disadvantages. The IBIP Open System Specification allows customers to use a generic “off the shelf” printer. As a result, these types of postage metering systems typically cost less because the customer is able to reuse its general office printer for printing postage. However, the IBIP Open System Specification requires that the recipient address (in the form of a delivery point zip code) be included in the postal indicium. This forces customers to input the destination address (either by hand or from a database) every time they want to print postage so that the recipient address and the corresponding postage indicium are generated and printed together as an integral unit. This is to ensure that address cleansing is performed and that there is a one to one correspondence between the recipient address and its associated postage indicium. As a result, the open system type of postage metering system must print this unit on the actual mail piece or label stock for later attachment to the mail piece.
On the other hand, the IBIP Closed System Specification do not require the delivery point zip code, but do require that the printer be a dedicated postage printing device. Thus, these types of postage metering systems allow for quicker transaction times for the customer (no need to input the recipient address, perform address hygiene or print the address) but cost more for the customer because of the investment necessary in a dedicated postage printer that has limited or no usefulness other than as a postage printing appliance.
Therefore, there is a need for a postage metering system that combines the operational efficiencies of a closed system meter with the cost advantages of an open system meter while satisfying the IBIP Specifications.